1. Field of the Invention
The present invention relates to a shock protection device for position measuring, probes or gyroscopes, in particular those which are equipped with an optical gyroscopic system or with a mechanical oscillator.
2. Description of the Related Art
A shock protection system for position measuring probes of the type, as described in the German patent references DE 19800534.2 or DE 19546405.2, is not known. The devices used by the person skilled in the art in order to protect chronometers or electric precision instruments such as, for example, galvanometers against shock cannot be used in this regard to provide shock protection for position measuring probes or gyroscopes.
The problem on which the invention is based consists in the following: when use is made of position measuring probes, they have to be protected against excessive shocks or accelerations. This is based, in particular, on the sensitivity of the components to such shocks. Substantial repair costs can therefore arise through inadvertently dropping such instruments. On the other hand, the position measuring probes must be applied to a surface to be measured in a defined fashion, that is to say with mechanical precision without backlash or damaging flexibility. These aspects oppose one another to a certain extent, since it is not possible to fit conventional cushioning to the probes discussed here without adversely affecting their measuring accuracy.
In accordance with the invention, the present problem is solved by providing the position measuring probes a shock protection which is temporarily deactivated on the occasion of a measuring operation to be carried out, or is made available only proportionally. For this purpose, in a first basic embodiment, the shock protection has the following features:
an outer housing shell is present which can be applied to a surface to be measured in a defined fashion,
at least one inner housing shell is present which encloses one or more sensors or instruments, in particular angular position sensors,
the inner housing shell is spaced apart by one or more cushioning or shock-absorbing elements with reference to an outer enclosing housing shell or a bearing surface during a time phase in which anti-shock functions are prioritized,
the inner housing shell is brought into self-closed mechanical contact with, reference to an enclosing outer housing shell or a bearing surface during a phase for detecting measured values, and
the inner housing shell can be brought into self-closed mechanical contact with the outer shell or a bearing surface by means of an electromechanical device or manually.
In a second basic embodiment, the shock protection according to the invention for a position measuring probe has the following features:
the position measuring probe can be brought into a first operating state by means of a device which can be actuated manually or by motor, in which it is protected completely against shocks acting from outside, but in which it cannot be used for the purposes of position measurement, and
the position measuring probe can be brought into a second operating state by: means of the device which can be actuated manually or by motor, in which it can carry out position measurements, but during the period of which it is not completely protected against shocks acting from outside.
It is now possible in accordance with the invention to protect position measuring probes and gyroscopes based on optical gyroscopes, specifically fiber-optic gyroscopes, and those having one or more mechanical vibrators (oscillators), against shocks during transportation, during operation and also when being applied to a surface to be measured. Such surfaces can specifically be the cylindrical surfaces of rollers such those used to produce films, foils, sheets and paper materials, and which must have a highly accurate parallelism. The invention is therefore, particularly suitable for carrying out a very accurate measurement of the parallelism of such rollers without there being a large risk of inadvertently damaging the relatively costly measuring apparatus used by incorrect deposition, mounting or by dropping.
In accordance with the first basic embodiment, the invention is based on the fact that instead of a single housing for appropriate devices, provision is now made of a housing which has an inner and an outer shell. The two shells are spaced apart from one another in the inactive state of the probe by a special cushion. A measuring system located inside the inner housing shell is thereby protected elastically against shocks. Not until shortly before the determination of a measured value and after the measuring probe has been brought into a measuring position of interest is an electrically operated device used to ensure that the inner and outer shells are brought into mechanical contact with one another which is defined with high accuracy. Immediately after the measured value is taken, it is ensured that the mechanical contact between the two shells is released again. Instead of the electrically operated device which makes the mechanical contact, it is also possible to provide a device which operates similarly and is to be actuated manually and which can be configured more simply in structural terms. A device operated by compressed air can also be provided for comparable problems requiring a relatively large housing. A typical cycle of a measuring operation thus consists in that the measuring probe is applied to a surface to be measured, a trip element or switch is then actuated by means of the electrically operated device to produce precise mechanical contact between the two shells, and an electronic system (preferably located in the interior of the two shells) then senses and electronically evaluates the positional and/or angular values of interest, and thereafter the mechanical contact between the two shells is released again by the electrically operated device. The measured values obtained are further used and evaluated after these steps.
In accordance with the invention, mechanical contact is made between the inner and outer shells preferably by means of a contact-making movement in the direction of one of the spaced diagonals of these shells, with the result that the periphery of the inner shell can make contact with at least three bearing points on the inside of the outer shell. The outer shell acts in this way to a certain extent, as a mechanical guide prism for the inner shell. It is possible in accordance with the invention to provide any desired elastic materials as cushioning for the purpose of absorbing shocks on the said inner shell with respect to the outer shell. However, it is advantageous to provide expanded silicone materials as cushioning, since not only can these be used over a large temperature range and are virtually nonflammable, but their elastic properties also show no particularly pronounced temperature response.